The present invention relates to a heat sink which mounts on a chassis and supports a circuit board. The heat sink also mounts at least one solid state device in proximity to the circuit board such that electrical connections from the solid state device to the circuit board are made without strain on the connections.
In present day power supplies, various components generate amounts of heat which cannot be adequately transferred to the ambient surroundings without the utilization of a heat sink. Printed circuit boards are used to provide a support for the electrical conductors and the associated electrical components, generally solid state devices, that make up the power supply. The high heat generating components are mounted to large heat sinks remote from the printed circuit board. This remote mounting is traditionally called "off-board" mounting. In order to have an effective transfer of heat from the solid state device to the heat sink the solid state device must be securely clamped to the heat sink. It is also highly desirable to have the solid state device mounted to the heat sink with a device that will permit its easy removal from the heat sink and also from the associated circuit board in case of component failure. It is also desirable to have the solid state device (heat generating device) in close proximity to its associated circuit board, so as to minimize the length of the conductors required for connecting the solid state device to the circuit board.
In U.S. Pat. No. 3,366,171, entitled "Heat Sink For Semi-Conductor Elements", by O. Scharli, there is disclosed a heat sink shaped as a right circular cylinder on its outer surface and having a tapered hexagon inner surface extending from one end to the other. Three semiconductor elements are pressed against flat portions of the inner surface by a truncated cone shaped element, which has a bolt assembly for urging the cone toward the narrow end of the inner surface so as to effectively wedge the semiconductor elements into thermal contact with the heat sink.
In U.S. Pat. No. 4,193,444, entitled "Electrical Mounting Means For Thermal Conduction", by R. L. Boyd et al., there is disclosed a U-shaped metal supporting element which has a tapered surface adjacent to the bottom of the U-shape, which tapered surface is designed to frictionally engage with a large complementary U-shaped member, such that pressure, exerted on the upper U-shaped member, causes the frictional engagement surfaces to experience an increased engagement force. A spring is used to provide the downward pressure instead of a bolt or screw type fastener so as to minimize fluctuations in the engagement force caused by thermal cycling of the components.
Another patent of interest for its teaching is U.S. Pat. No. 4,204,248, entitled "Heat Transfer Mounting Arrangement for a Solid State Device Connected to a Circuit Board", by D. S. Proffit et al. In this patent a solid state device is fastened to a metallic heat sink which heat sink, in turn, is connected to a chassis in close proximity to a like mounted circuit board, such that the electrical leads from the solid state device may be connected to the printed circuit board without strain.
Still another device of interest is disclosed in U.S. Pat. No. 4,475,145, entitled "Circuit Board Heatsink Assembly and Technique", by D. L. Heil et al. In this patent there is disclosed a device for increasing the heat transfer between a circuit board and a metal chassis acting as a heat sink. The device is comprised of two wedges, one of which contains an elongated opening and the other of which contains a circular opening. A fastener (machine screw) passing through the wedge openings engages a portion of the chassis and when drawn down causes the wedge with the elongated opening to move in a direction which increases the engagement force between a captured portion of a circuit board and the chassis.